A Jedi From Earth Wikia

The Imperial Security Bureau (ISB), also referred to as the Security Bureau or Imperial Security, was a law enforcement and intelligence agency of the Galactic Empire that was charged with matters of state security and ensuring the loyalty of citizens to the Empire. Aside from that, it happened to be one of the many umbrella organizations under the greater Commission for the Preservation of the New Order, and was larger than Imperial Intelligence. The organization largely operated a secret police


(Source star wars wika)